Hardness tester



FIG. 1 is a front, right-side, top perspective view of the hardness tester;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a right-side elevational view thereof;

FIG. 5 is a left-side elevational view thereof;

FIG. 6 is a rear elevational view thereof; and,

FIG. 7 is a bottom plan view thereof.

The broken lines depict unclaimed parts of the hardness tester, and thus form no part of the claimed design. 

CLAIM The ornamental design for a hardness tester, as shown and described. 